ds_monitoring.c

/* 
 * Data Structure Monitoring implementation
 * 
 * Author: Seokjoo Cho, <lnxlht4j@gmail.com> 
 */

#include "ds_monitoring.h"
#include <linux/slab.h>
#include <linux/string.h>

extern const char *dm_name;

/*
 * Creates new ds_monitoring_elem from @elem and append it into the XArray.
 */
static void
insert_ds_monitoring(struct ds_monitoring *dm, unsigned long index, void *elem)
{
	const char *name;
	struct ds_monitoring_elem *new;
	
	new = kmalloc(sizeof(struct ds_monitoring_elem), GFP_KERNEL);
	new->key = index;
	new->count = 1;

	if (dm->dm_ops->get_name) {
		name = dm->dm_ops->get_name(elem);
		new->name = kmalloc(strlen(name)+1, GFP_KERNEL);
		strcpy(new->name, name);
	} else {
		new->name = NULL;
	}

	xa_store(dm->elements, new->key, (void*) new, GFP_KERNEL);
#ifdef __CONFIG_DM_DEBUG
	printk("ds_monitoring: Inserted element[%lu] @%px into %s\n", 
			index, new, dm_name);
#endif
}

/*
 * Find if ds_monitoring_elem of @elem is in Xarray.
 * If found, increase referenced count.
 * If not, create a new ds_monitoring_elem for @elem.
 */
void find_ds_monitoring(struct ds_monitoring *dm, void *elem)
{
	struct ds_monitoring_elem *cur;
	unsigned long xa_index;

	if (dm->dm_ops->get_index) {
		xa_index = dm->dm_ops->get_index(elem);

		// search ds_monitoring_elem at index of xa_index from xarray root 
		cur = (struct ds_monitoring_elem *) xa_load(dm->elements, xa_index);

		if (cur)
			__sync_fetch_and_add(&cur->count, 1);
		else
			insert_ds_monitoring(dm, xa_index, elem);

		__sync_fetch_and_add(&dm->total_counts, 1);
	}
}

/*
 * Dump all the ds_monitoring_elem information in the ds_monitoring.
 */
void print_ds_monitoring(struct ds_monitoring* dm)
{
	unsigned long cur_idx;
	void *cur;
	char *cur_name;
	unsigned long long cur_count;
	int percentage;

	if (!dm->total_counts || !dm->dm_ops->print_elem)
		return;
	
	// iterates xarray elements
	xa_for_each(dm->elements, cur_idx, cur) {
		cur_name = ((struct ds_monitoring_elem *)cur)->name;
		cur_count = ((struct ds_monitoring_elem *)cur)->count;
		percentage = cur_count  * 100 / dm->total_counts;
		dm->dm_ops->print_elem(cur_idx, cur_name, cur_count, percentage);
	}
}


/*
 * Frees all the allocated memory for ds_monitoring, and then destroys it.
 */
void delete_ds_monitoring(struct ds_monitoring *dm)
{
	unsigned long cur_idx;
	void *cur;
	char *cur_name;

	// iterates xarray elements
	xa_for_each(dm->elements, cur_idx, cur) {
		cur_name = ((struct ds_monitoring_elem *)cur)->name;
		kfree(cur_name);
		kfree(cur);
#ifdef __CONFIG_DM_DEBUG
		printk("ds_monitoring: Deleted element[%lu] @%px from %s\n", 
				cur_idx, cur, dm_name);
#endif
	}
	xa_destroy(dm->elements);
}